I've just set up my grow room dimesnions of which are 22"D x 29"W x 65" height. I have bought envirolights to light it with 1 x 125w blue and 1 x 125w red. I can only run one light at a time and currently have the blue light plugged in. I have an RKV125 fan with carbon filter, a passive intake setup (at elast I think that's what it is!) through louvre doors using charcoal cooker hood filters and an oscillating fan at the bottom of the cupboard. I have kept it all running for a couple of days before I put plants in there to check it's all working right and have noted that my temps are pretty much perfect, 75 during the day and 65 at night.

My question is this, I was considering using a 250w HPS lamp for flowering, for the extra yeild (until headroom becomes a problem and then switch over to the 125w red enviro to finish the job) but as my temps are running great with the enviro lamp, I was wondering if it was worth using an hps lamp considering the heat this will produce (and not having an intake fan) it will probably mess up my temps. Is the extra yeild I would get from the hps worth the potential problems it will probably cause using it? Am I better off using the enviro's for the whole grow? I'm planning to grow two northern lights for my 1st growing attempts.

Cheers,

San

cut some holes in the bottom of the drobe, cover them with spare cooker hood filter to block light entering and that will be a couple of passive intakes, should get a better draught through there for ya
T1

I can't cut holes in the doors, not allowed They are louvre doors though and I do have carbon filters at the bottom of them. I don't actually have an hps lamp yet so don't want to fork out on one until I've asked if it's worth it. As it is I probably wouldn't be able to use it for too long because of the head room (have about 4ft under the lamp to the floor) so don't know if it's worth it for the extra yeild I would get.

dont cut them in the doors, cut them in the sides near the bottom

You are right of course. See what I can get out of them with the enviro's 1st. anyone would think I'd been smoking all day to have to ask the question and not come up with that answer on my own. Just wondered how much difference it would actually make to my yeild and my environment under my circs.

That's a no go too I'm afraid as my drobes are all built in. My rkv has gone through a cupboard above the drobe so that's not noticeable from the outside

other option if you wanna go with the HPS, use an oscilating fan in there and point it to the light, that will blow away moost of the heat letting you get the hps closer to the plants
all idea's you need to decide what to do
Peace t1

Looks good, should stop worrying really but I'm concerned about the amount of yeild from enviro's is poorer than that of hps and don't know if it's going to last me through to the next grow. No point shelling out all this cash on a gr if I then have to go out and source as well.

Thanks for all the input guys, mucho appreicated

There's not much point letting plants get tall enough for headroom to be an issue though, whether using Enviros or a 250 HPS.. neither have the power to reach very far down the plant. I find 60 to 80cm is about as tall as you want to go with a 250. Providing your intakes are big enough there's no reason why you couldn't use an HPS in there.. an RVK125 has a huge amount of suck for a space that size so it's only the radiant heat from the bulb to deal with (which as already mentioned can be dealt with by aiming a fan at the bulb)